CVE-2022-50459

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: iscsi: iscsi_tcp: Fix null-ptr-deref while calling getpeername() Fix a NULL pointer crash that occurs when we are freeing the socket at the same time we access it via sysfs. The problem is that: 1. iscsi_sw_tcp_conn_get_param() and iscsi_sw_tcp_host_get_param() take the frwd_lock and do sock_hold() then drop the frwd_lock. sock_hold() does a get on the "struct sock". 2. iscsi_sw_tcp_release_conn() does sockfd_put() which does the last put on the "struct socket" and that does __sock_release() which sets the sock->ops to NULL. 3. iscsi_sw_tcp_conn_get_param() and iscsi_sw_tcp_host_get_param() then call kernel_getpeername() which accesses the NULL sock->ops. Above we do a get on the "struct sock", but we needed a get on the "struct socket". Originally, we just held the frwd_lock the entire time but in commit bcf3a2953d36 ("scsi: iscsi: iscsi_tcp: Avoid holding spinlock while calling getpeername()") we switched to refcount based because the network layer changed and started taking a mutex in that path, so we could no longer hold the frwd_lock. Instead of trying to maintain multiple refcounts, this just has us use a mutex for accessing the socket in the interface code paths.

Gravité et risque d'exploitation

CVE-2022-50459 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.18 %, ce qui la place devant 6.6 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <897dbbc57d71e8a34ec1af8e573a142de457da38, <0a0b861fce2657ba08ec356a74346b37ca4b2008, 0, 7d29e950766327f658cb92722b9445ac3b3ae023, <a26b0658751bb0a3b28386fca715333b104d32a2, <=5.10.*, <=6.0.*, 5.9, bcf3a2953d36bbfb9bd44ccb3db0897d935cc485, <5.9, 6.1, 5.19.17, <=*, <=5.15.*, <57569c37f0add1b6489e1a1563c71519daf732cf, 5.8.14, 6.0.3, <=5.19.*, <884a788f065578bb640382279a83d1df433b13e6, 5.15.75, 5.10.150) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/884a788f065578bb640382279a83d1df433b13e6
• https://git.kernel.org/stable/c/a26b0658751bb0a3b28386fca715333b104d32a2
• https://git.kernel.org/stable/c/897dbbc57d71e8a34ec1af8e573a142de457da38
• https://git.kernel.org/stable/c/0a0b861fce2657ba08ec356a74346b37ca4b2008
• https://git.kernel.org/stable/c/57569c37f0add1b6489e1a1563c71519daf732cf